Prior art fluid dispensers, e.g. for dispensing fluids into a nasal cavity, are known from US-A-2005/0236434 and WO-A-2005/075103, the entire original disclosures of which (as well as their patent family members) are incorporated herein by way of reference. These dispensers comprise a fluid reservoir, an outlet and a pump for pumping fluid from the reservoir through the outlet. The outlet is provided in a nozzle, which nozzle may be shaped and sized for positioning in a nostril. As the dispensers are for dispensing a metered volume of the fluid, they further comprise a metering chamber which is selectively placed in fluid communication with the reservoir, through at least one metering chamber inlet, and the outlet. The pump reciprocates to move the metering chamber between an expanded state, in which the metering chamber has a first volume greater than the metered volume, and a contracted state. The dispensers further comprise a one-way valve between the metering chamber and the outlet which is biased to a ‘valve-closed’ position. When the metering chamber moves from its contracted state to its expanded state, the metering chamber and reservoir are placed in fluid communication through the at least one inlet and fluid is drawn from the reservoir into the metering chamber to fill the metering chamber with an excess volume of fluid. When the metering chamber moves from the expanded state towards the contracted state, there is an initial bleed phase in which the surplus volume of fluid in the metering chamber is pumped back into the reservoir through the at least one inlet to leave a metered volume of fluid in the metering chamber. In a final dispensing phase of movement of the metering chamber back to its contracted state, the metered volume of fluid in the metering chamber is pumped towards the one-way valve whereby the increasing pressure produced in the fluid causes the one-way valve to temporarily open to enable the metered volume to be pumped from the outlet.
Other fluid dispenser arrangements are disclosed in FIGS. 1 to 21 of WO-A-2007/138084.
An aim of the present invention is to provide a novel fluid dispenser and novel components for a fluid dispenser, which fluid dispenser optionally incorporates the pumping principle disclosed in US-A-2005/0236434 and WO-A-2005/075103.